On Fri, Oct 25, 2019 at 8:16 AM Christian König
<ckoenig.leichtzumerken@xxxxxxxxx> wrote:
>
> Add an DMA-buf export implementation independent of the DRM helpers.
>
> This not only avoids the caching of DMA-buf mappings, but also
> allows us to use the new dynamic locking approach.
>
> This is also a prerequisite of unpinned DMA-buf handling.
>
> v2: fix unintended recursion, remove debugging leftovers
> v3: split out from unpinned DMA-buf work
> v4: rebase on top of new no_sgt_cache flag
> v5: fix some warnings by including amdgpu_dma_buf.h
> v6: fix locking for non amdgpu exports
> v7: rebased on new DMA-buf locking patch
>
> Signed-off-by: Christian König <christian.koenig@xxxxxxx>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 172 +++++++++++---------
> drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h | 1 -
> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 1 -
> drivers/gpu/drm/amd/amdgpu/amdgpu_object.c | 1 +
> 4 files changed, 97 insertions(+), 78 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> index 61f108ec2b5c..f14b52cc7205 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c
> @@ -34,26 +34,11 @@
> #include "amdgpu.h"
> #include "amdgpu_display.h"
> #include "amdgpu_gem.h"
> +#include "amdgpu_dma_buf.h"
> #include <drm/amdgpu_drm.h>
> #include <linux/dma-buf.h>
> #include <linux/dma-fence-array.h>
>
> -/**
> - * amdgpu_gem_prime_get_sg_table - &drm_driver.gem_prime_get_sg_table
> - * implementation
> - * @obj: GEM buffer object (BO)
> - *
> - * Returns:
> - * A scatter/gather table for the pinned pages of the BO's memory.
> - */
> -struct sg_table *amdgpu_gem_prime_get_sg_table(struct drm_gem_object *obj)
> -{
> - struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
> - int npages = bo->tbo.num_pages;
> -
> - return drm_prime_pages_to_sg(bo->tbo.ttm->pages, npages);
> -}
> -
> /**
> * amdgpu_gem_prime_vmap - &dma_buf_ops.vmap implementation
> * @obj: GEM BO
> @@ -179,92 +164,126 @@ __dma_resv_make_exclusive(struct dma_resv *obj)
> }
>
> /**
> - * amdgpu_dma_buf_map_attach - &dma_buf_ops.attach implementation
> - * @dma_buf: Shared DMA buffer
> + * amdgpu_dma_buf_attach - &dma_buf_ops.attach implementation
> + *
> + * @dmabuf: DMA-buf where we attach to
> + * @attach: attachment to add
> + *
> + * Add the attachment as user to the exported DMA-buf.
> + */
> +static int amdgpu_dma_buf_attach(struct dma_buf *dmabuf,
> + struct dma_buf_attachment *attach)
> +{
> + struct drm_gem_object *obj = dmabuf->priv;
> + struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
> + struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> + int r;
> +
> + if (attach->dev->driver == adev->dev->driver)
> + return 0;
> +
> + r = amdgpu_bo_reserve(bo, false);
> + if (unlikely(r != 0))
> + return r;
> +
> + /*
> + * We only create shared fences for internal use, but importers
> + * of the dmabuf rely on exclusive fences for implicitly
> + * tracking write hazards. As any of the current fences may
> + * correspond to a write, we need to convert all existing
> + * fences on the reservation object into a single exclusive
> + * fence.
> + */
> + r = __dma_resv_make_exclusive(bo->tbo.base.resv);
> + if (r)
> + return r;
> +
> + bo->prime_shared_count++;
> + amdgpu_bo_unreserve(bo);
> + return 0;
> +}
> +
> +/**
> + * amdgpu_dma_buf_detach - &dma_buf_ops.detach implementation
> + *
> + * @dmabuf: DMA-buf where we remove the attachment from
> + * @attach: the attachment to remove
> + *
> + * Called when an attachment is removed from the DMA-buf.
> + */
> +static void amdgpu_dma_buf_detach(struct dma_buf *dmabuf,
> + struct dma_buf_attachment *attach)
> +{
> + struct drm_gem_object *obj = dmabuf->priv;
> + struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
> + struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> +
> + if (attach->dev->driver != adev->dev->driver && bo->prime_shared_count)
> + bo->prime_shared_count--;
> +}
> +
> +/**
> + * amdgpu_dma_buf_map - &dma_buf_ops.map_dma_buf implementation
> * @attach: DMA-buf attachment
> + * @dir: DMA direction
> *
> * Makes sure that the shared DMA buffer can be accessed by the target device.
> * For now, simply pins it to the GTT domain, where it should be accessible by
> * all DMA devices.
> *
> * Returns:
> - * 0 on success or a negative error code on failure.
> + * sg_table filled with the DMA addresses to use or ERR_PRT with negative error
> + * code.
> */
> -static int amdgpu_dma_buf_map_attach(struct dma_buf *dma_buf,
> - struct dma_buf_attachment *attach)
> +static struct sg_table *amdgpu_dma_buf_map(struct dma_buf_attachment *attach,
> + enum dma_data_direction dir)
> {
> + struct dma_buf *dma_buf = attach->dmabuf;
> struct drm_gem_object *obj = dma_buf->priv;
> struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
> - struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> + struct sg_table *sgt;
> long r;
>
> - r = drm_gem_map_attach(dma_buf, attach);
> - if (r)
> - return r;
> -
> - r = amdgpu_bo_reserve(bo, false);
> - if (unlikely(r != 0))
> - goto error_detach;
> -
> -
> - if (attach->dev->driver != adev->dev->driver) {
> - /*
> - * We only create shared fences for internal use, but importers
> - * of the dmabuf rely on exclusive fences for implicitly
> - * tracking write hazards. As any of the current fences may
> - * correspond to a write, we need to convert all existing
> - * fences on the reservation object into a single exclusive
> - * fence.
> - */
> - r = __dma_resv_make_exclusive(bo->tbo.base.resv);
> - if (r)
> - goto error_unreserve;
> - }
> -
> - /* pin buffer into GTT */
> r = amdgpu_bo_pin(bo, AMDGPU_GEM_DOMAIN_GTT);
> if (r)
> - goto error_unreserve;
> + return ERR_PTR(r);
>
> - if (attach->dev->driver != adev->dev->driver)
> - bo->prime_shared_count++;
> + sgt = drm_prime_pages_to_sg(bo->tbo.ttm->pages, bo->tbo.num_pages);
> + if (IS_ERR(sgt))
> + return sgt;
>
> -error_unreserve:
> - amdgpu_bo_unreserve(bo);
> + if (!dma_map_sg_attrs(attach->dev, sgt->sgl, sgt->nents, dir,
> + DMA_ATTR_SKIP_CPU_SYNC))
> + goto error_free;
>
> -error_detach:
> - if (r)
> - drm_gem_map_detach(dma_buf, attach);
> - return r;
> + return sgt;
> +
> +error_free:
> + sg_free_table(sgt);
> + kfree(sgt);
> + return ERR_PTR(-ENOMEM);
> }
>
> /**
> - * amdgpu_dma_buf_map_detach - &dma_buf_ops.detach implementation
> - * @dma_buf: Shared DMA buffer
> + * amdgpu_dma_buf_unmap - &dma_buf_ops.unmap_dma_buf implementation
> * @attach: DMA-buf attachment
> + * @sgt: sg_table to unmap
> + * @dir: DMA direction
> *
> * This is called when a shared DMA buffer no longer needs to be accessible by
> * another device. For now, simply unpins the buffer from GTT.
> */
> -static void amdgpu_dma_buf_map_detach(struct dma_buf *dma_buf,
> - struct dma_buf_attachment *attach)
> +static void amdgpu_dma_buf_unmap(struct dma_buf_attachment *attach,
> + struct sg_table *sgt,
> + enum dma_data_direction dir)
> {
> - struct drm_gem_object *obj = dma_buf->priv;
> + struct drm_gem_object *obj = attach->dmabuf->priv;
> struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
> - struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
> - int ret = 0;
> -
> - ret = amdgpu_bo_reserve(bo, true);
> - if (unlikely(ret != 0))
> - goto error;
>
> + dma_unmap_sg(attach->dev, sgt->sgl, sgt->nents, dir);
> + sg_free_table(sgt);
> + kfree(sgt);
> amdgpu_bo_unpin(bo);
> - if (attach->dev->driver != adev->dev->driver && bo->prime_shared_count)
> - bo->prime_shared_count--;
> - amdgpu_bo_unreserve(bo);
> -
> -error:
> - drm_gem_map_detach(dma_buf, attach);
> }
>
> /**
> @@ -308,10 +327,11 @@ static int amdgpu_dma_buf_begin_cpu_access(struct dma_buf *dma_buf,
> }
>
> const struct dma_buf_ops amdgpu_dmabuf_ops = {
> - .attach = amdgpu_dma_buf_map_attach,
> - .detach = amdgpu_dma_buf_map_detach,
> - .map_dma_buf = drm_gem_map_dma_buf,
> - .unmap_dma_buf = drm_gem_unmap_dma_buf,
> + .dynamic_mapping = true,
> + .attach = amdgpu_dma_buf_attach,
> + .detach = amdgpu_dma_buf_detach,
> + .map_dma_buf = amdgpu_dma_buf_map,
> + .unmap_dma_buf = amdgpu_dma_buf_unmap,
> .release = drm_gem_dmabuf_release,
> .begin_cpu_access = amdgpu_dma_buf_begin_cpu_access,
> .mmap = drm_gem_dmabuf_mmap,
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h
> index 5012e6ab58f1..ce1b3f017451 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h
> @@ -25,7 +25,6 @@
>
> #include <drm/drm_gem.h>
>
> -struct sg_table *amdgpu_gem_prime_get_sg_table(struct drm_gem_object *obj);
> struct drm_gem_object *
> amdgpu_gem_prime_import_sg_table(struct drm_device *dev,
> struct dma_buf_attachment *attach,
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> index 4da1d7fb10f4..8805776c8c52 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
> @@ -1445,7 +1445,6 @@ static struct drm_driver kms_driver = {
> .prime_fd_to_handle = drm_gem_prime_fd_to_handle,
> .gem_prime_export = amdgpu_gem_prime_export,
> .gem_prime_import = amdgpu_gem_prime_import,
> - .gem_prime_get_sg_table = amdgpu_gem_prime_get_sg_table,
> .gem_prime_import_sg_table = amdgpu_gem_prime_import_sg_table,
> .gem_prime_vmap = amdgpu_gem_prime_vmap,
> .gem_prime_vunmap = amdgpu_gem_prime_vunmap,
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> index 6f0b789a0b49..b319254537b8 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_object.c
> @@ -31,6 +31,7 @@
> */
> #include <linux/list.h>
> #include <linux/slab.h>
> +#include <linux/dma-buf.h>
Is this change intended?
Alex
>
> #include <drm/amdgpu_drm.h>
> #include <drm/drm_cache.h>
> --
> 2.17.1
>
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